Nine young, highly venomous snakes are safely slithering in the viper room of the Saint Louis Zoo today, thanks to a breeding program that may help to save the species from extinction after overzealous collectors nearly eradicated it from its natural range.
The critically endangered ocellate mountain viper (Vipera wagneri) has a long and problem-plagued history. First scientifically described by German naturalist Moritz Wagner in 1846 and then unseen for 140 years, many assumed the species had gone extinct.
Wagner initially described the species as Vipera aspsis ocellatta, a subspecies of another large viper found in the region. Scientists that followed didn't agree with Wagner’s assessment, alternately suggesting the sample was really from one of two similar species, the Ottoman viper (V. xanthina) or the Armenian viper (V. raddei). Those scientists, however, were using Wagner's written descriptions. In 1984 Göran Nilson and Claes Andrén, biologists at the University of Gothenburg in Sweden, tracked down Wagner's original sample in the Alexander Koenig Museum in Germany. Their physical examination demonstrated that it was neither xanthina nor raddei. They came up with the name V. wagneri (sometimes referred to as Montivipera wagneri).
But at that point the question remained, where was wagneri? Was the meter-long snake extinct or was it still hiding somewhere in Iran?
It turns out that the answer to both of those questions was "no." At about the same time that Nilson and Andrén were redescribing the species, a group of German entomologists found a live snake on a road—not in Iran but across the border in eastern Turkey. German and French scientific journals published the news in 1986, identifying the location. Meanwhile examination of Wagner's original specimen revealed that its site of origin had been mislabeled. Wagner had been exploring what was then known as the Colchis region, which today includes parts of Iran, Turkey, Georgia and Russia, and tagged the snake with the wrong site. As it turned out, the rocky, moist region of eastern Turkey was actually the long-lost snake's home.
But after 140 years in hiding that rediscovery put a target on the snake's back. As Nilson and Andrén wrote in 1999 in their keynote address (pdf) to a snake conservation workshop, "Wagner's viper is a rather handsome snake, and once the distribution was discovered and more widely known... a number of groups of viper collectors (mainly European) went to the known valley in east Turkey and collected large numbers of vipers. It seems that many pregnant females were removed from this location, and about ten years ago it was easy to find newborns of this species listed for sale by European dealers and terrarium societies."
Seeing the danger that this collection posed, Nilson and Andrén worked to get the species listed under Appendix II of the Convention on International Trade in Endangered Species (CITES), which banned international trade of the species without export permits. But the damage was already done. In 2009, with populations down at least 80 percent and a new dam on the Aras River threatening to destroy a large portion of the snake's habitat, the International Union for Conservation of Nature listed the ocellate mountain viper as "critically endangered."
All of which brings us to today. The Saint Louis Zoo coordinates a Species Survival Plan (based on the programs created by the American Association of Zoos and Aquariums) for the ocellate mountain viper, which includes a cooperative breeding program among several zoos. There aren't many zoos that hold these snakes, though. Saint Louis is one of only three in the U.S. with the species in their collections, and they have the majority: Including the nine snakes born on August 16, Saint Louis Zoo has 23 of the 28 ocellate mountain vipers in the U.S. The zoo already had experience with the related Armenian viper and the information gained from breeding the ocellate vipers should help to improve breeding efforts in other facilities.
The snake still remains critically endangered in the wild, a situation that probably won't change anytime soon. Collectors still value the viper, and its already small habitat area still faces the threat of development.
Back in 1999 Nilson and Andrén asked if it was wrong to publish the ocellate mountain viper's location, a question worth asking anytime a species is located, especially if it holds monetary value. They argued that the scientific value outweighed the risk, writing "it is only possible to protect species when we know of their existence, and to protect their habitats and range when we know about their biology and distribution. Collecting is one serious problem for rare species, but there are other threats that are much worse, such as habitat destruction [and] pollution."
The ocellate mountain viper may not ever thrive in the wild the way it once did, but because of the work of scientists at the Saint Louis Zoo and other facilities, they may not go extinct either.
Photo: Mark Wanner, Saint Louis Zoo